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The Port State Jurisdiction of a coastal state over a ship that voluntarily enters its port, having violated marine pollution laws on the High Seas or in the jurisdictional zones of other coastal states


The Port State Jurisdiction of a coastal state over a ship that voluntarily enters its port, having violated marine pollution laws on the High Seas or in the jurisdictional zones of other coastal states


The Port state jurisdiction (control) is the jurisdiction that a coastal state exercises in relation to breach of regulations and laws that have occurred outside its jurisdictional ambit. Clearly such jurisdiction must be exercised, following the request of the flag state or by virtue of enforcement rights granted by the flag state or the state where the breach of regulation or law has taken place under an international agreement (Art 218 of the United Nations Convention on the Law of the Sea). The prescriptive and enforcement jurisdiction comprise the main jurisdictions of a state. Prescriptive is the jurisdiction to prescribe laws and regulations and Enforcement is the jurisdiction to enforce such laws.

The Customary International Law is one of the main sources of International Law, involving the principle of custom. The International Court of Justice Statute defines customary international law in Article 38(1)(b) as "evidence of a general practice accepted as law”. This is generally determined through two factors: Firstly, the general practice of states (the objective element) and secondly, the opinion juris i.e. what states have accepted as law (subjective element).

The North Sea Continental Shelf Cases confirmed that both State practice (the objective element) and opinio juris (the subjective element), are essential pre-requisites for the formation of a customary law rule. 

a)       Prescriptive rights

Under Art. 211(2) and 211(5) the United Nations Convention on the Law of the Sea entitles the coastal states to prescribe such obligations (applicable international rules and standards established through the IMO or general diplomatic conference) for their jurisdictional zones. However, the better view is that Art. 218 does not create port state jurisdiction in relation to laws and rules for which neither the flag state of the ship nor the coastal state where the discharge took place have provided for.

Last but not least, regional voluntary agreements developed under the IMO auspices like the Memorandum of Understanding on Port State (Paris MOU) provide for cooperative port state inspection system to ensure compliance with international standards.

b)      Enforcement rights

Express enforcement rights are granted to port states under Article 218 Unclos. The aforementioned article deals with breaches of internationally agreed rules in areas outside the jurisdiction of the port state (paragraph 1), but not in areas within the jurisdiction of another state (paragraph 2), unless the other state (the flag state, the foreign state in which the discharge occurred or another state that has suffered damage) has required action by the port state or the port state has also suffered pollution. Such enforcement rights are granted in relation of international rules and standards. Art. 218 grants jurisdiction to undertake investigations and institute proceedings, but only where there is discharge which violates applicable international rules and standards established through the IMO or general diplomatic conference, but also standards in regional and bilateral agreements. Thus, for breach of such rules the port state may start investigations for discharges in the high seas.

However, there is an ambiguity in relation to the scope of the application of the port state control. In particular, it is questionable whether Art. 218(1) applies to IMO rules only where the flag state is a contracting state to these IMO rules or whether compliance with such rules can be enforced even if the flag state is not a contracting state to the particular rules.

In addition, in case the violation occurred in the high sea or in the jurisdictional zones of other coastal states, the provisions of MARPOL also have to be activated. The agreement on the 1973 International Convention for the Prevention of Pollution from Ships (MARPOL 73) created a new framework for control of oil discharges but also for discharges of other substances. According to Article 4(1) MARPOL, there is a flag state enforcement obligation. Violation of MARPOL within the jurisdiction of a party to the Convention leads to either reference to flag state or initiation of proceedings by that member state (Art. 4(2) MARPOL).

At port validity certificate is the only permissible control unless there are “clear grounds” of non-conformity with the certificate. (Art. 5(2) MARPOL). Inspection for verification of particular incidents is also permitted (Art. 6(2) MARPOL), however, if the inspection finds indications of violations then these must be reported to the flag state. The flag state will decide on sufficiency of evidence and proceedings.

c)       Customary International Law

Overall, there is limited jurisdiction by the coastal state on the high seas under customary international law and Unclos. The basic regime is the exclusive flag state jurisdiction as per Art 94 Unclos. The coastal states do not have prescriptive rights for foreign flag ships, nor do they have enforcement rights, except in particular circumstances (e.g. Art 11(2)). Moreover, there is, no state practice to suggest that enforcement for discharges at the high seas is in use.

The most important authority, regarding the high sea is the Lotus case, which established two (2) principles. The first principle states that a state cannot exercise its jurisdiction in any form outside its territory unless an international treaty or customary law permits it to do so (para. 45). This is what is called the first principle of the Lotus case. The second principle states that within the state's territory, a state may exercise its jurisdiction, in any matter, even if there is no specific rule of international law permitting it to do so (paras 46-47). In these instances, states have a wide measure of discretion, which is only limited by the prohibitive rules of international law. However, the crucial question on here is whether the Lotus case can be applicable or not, since refers to a crime occurred on high seas and not for violations of marine pollution laws and regulations. If so, then the Lotus case is applicable, if not then, it cannot be considered as a customary law for this specific case.

In addition, customary international law can be seen in the High seas Convention 1958, in the 1958 Geneva Conventions on the Law of the Sea and in 1969 International Convention relating to Intervention on the High seas in case of oil pollution Casualties.

As far as the ports are concerned, there is no right of entry into ports of foreign states in customary International law, reasoning from the Nicaragua case. However, for humanitarian and safety reasons, it is generally recognised that any foreign vessel in distress has a right of entry to any foreign port under Customary International Law (e.g. The Nicaragua case para 123, Creole case 1853, The Carlo-Alberto case 1832 and The Eleanor Case 1808).

The Barcelona Traction case, suggests that there is a right to exercise jurisdiction on ships voluntarily entering the ports of a state, while in Nicaragua case, was held that the state can deny the entrance of a foreign vessels to its port.

The same consideration with the application of Lotus as mentioned above, exists in Poulsen Case, where a Danish port enforced its port jurisdiction, confiscating 22 tons of Salmon cought outside the waters of a European member state.

Furthermore, despite the fact that the Convention on the Law of the Sea is silent as to whether foreign ships have a right of access to a port, there is a general principle that a state does not have unlimited power to prohibit access to its port. In Saudi-Arabia v Aramco arbitration, the arbitrator observed that according to a great principle of public International law, the ports of every state must be open to foreign merchant vessels and can only be closed when the vital interests of the State so require.

In the New Zealand case it was held that it was an essential feature of the freedom of the high seas and the freedom of navigation that the state of nationality of a ship (the flag state) had exclusive jurisdiction over the ship when it was on the high seas. In addition, under the rules of international law a port state had no general power to unilaterally impose its own requirements on foreign ships relating to their construction, their safety and other equipment and their crewing if the requirements were to have effect on the high seas. Any requirements could not go beyond those generally accepted, especially in the maritime conventions and regulations.

Author: Zacharias L. Kapsis